The cornea relies greatly upon its material properties in its roles as a mechanical barrier to injury and as a scaffold for the eye's primary refracting surface. These biomechanical properties influence the safety and optical predictability of surgery and play an important role in the pathogenesis and of diseases such as keratoconus and post-refractive surgery ectasia. Consequently, alteration of these properties by disease or surgery can have profound visual implications. Ectatic diseases such as keratoconus, pellucid marginal degeneration and keratoglobus are characterized by progressive thinning and distortion of the cornea, and as a class represent a leading indication for corneal transplantation. Identification of early ectasia is a major emphasis of preoperative refractive surgery evaluations, where it is imperative to avoid the potential destabilizing effects of laser vision correction in corneas that are predisposed to biomechanical instability or failure.
Current screening tools are hampered by a reliance on late features of disease and a lack of tools for detecting sub-clinical abnormalities of elastic or viscoelastic behavior. In addition to playing a key role in the pathophysiology of keratectasia, corneal biomechanical properties influence the predictability of optical outcomes after laser in-situ keratomileusis (LASIK), photorefractive keratectomy (PRK) and other corneal surgeries. Corneal rigidity is also a poorly-characterized confounder of clinical intraocular pressure (IOP) measurement, and therefore its measurement has great relevance in the diagnosis and management of glaucoma.